Driving data recording device, method and computer program product

Abstract

The invention relates to a driving data recording device, a method and a computer program product. This travel data recording device is provided with: a storage processing unit (21) that stores travel data of a vehicle (1) in a volatile memory (12); a first copy processing unit (22) that copies and stores the travel data stored in the volatile memory (12) in one of the first non-volatile memory (13) and the second non-volatile memory (14) every time a first period has elapsed; and a second copy processing unit (24) that copies the event when a back-off timing is reached after a predetermined time has elapsed from the timing at which the occurrence of the predetermined event has been detected. And a copying unit that copies, from among the travel data stored in the one non-volatile memory, travel data for a second period, which includes the timing at which the occurrence of the event is detected and is longer than the first period, from among the travel data stored in the one non-volatile memory, and stores the travel data in the other non-volatile memory.

Description

Technical Field

[0001] The present invention relates to a travel data recording device, a travel data recording method, and a computer program for recording travel data for recording data obtained during travel of a vehicle. Background Art

[0002] A technology for recording data of a vehicle during travel has been proposed (see Japanese Patent Application Laid-Open No. 2013-73610).

[0003] In the technology disclosed in Japanese Patent Application Laid-Open No. 2013-73610, an information processing device overwrites first vehicle data for T1 seconds with older data and stores it in volatile memory until a predetermined vehicle condition is detected. Upon detection of the vehicle condition, second vehicle data for T2 seconds is stored in the volatile memory. Furthermore, upon detection of the vehicle condition, the information processing device records the first vehicle data from the volatile memory to the non-volatile memory, and records the second vehicle data from the volatile memory to the non-volatile memory at any time until all T2 seconds of second vehicle data are stored in the volatile memory.

[0004] In order to analyze the details of an event that occurred while a vehicle was traveling, it is sometimes insufficient to use only vehicle data before and after the event. Summary of the Invention

[0005] Therefore, an object of the present invention is to provide a driving data recording device capable of recording driving data of a vehicle over a relatively long period of time, wherein the relatively long period includes timings when events occur during driving of the vehicle.

[0006] According to one embodiment, a driving data recording device is provided. The driving data recording device includes: a volatile memory; a first non-volatile memory; a second non-volatile memory; a storage processing unit that stores driving data representing a condition of a vehicle during driving or a condition surrounding the vehicle in the volatile memory; a first copy processing unit that copies the driving data for the first period stored in the volatile memory and stores it in one of the first and second non-volatile memories each time a first period elapses; and a second copy processing unit that, when a retreat timing is reached that is a predetermined time after a predetermined time has elapsed since a timing at which a predetermined event is detected, copies the driving data for a second period from the first non-volatile memory and stores it in the other of the first and second non-volatile memories, wherein the second period includes the timing at which the event is detected and is longer than the first period.

[0007] In one embodiment, the driving data recording device further includes: a sending processing unit that determines whether the data volume of the driving data of the second period is less than or equal to a specified sending upper limit threshold. If the data volume is less than or equal to the sending upper limit threshold, the sending processing unit sends the driving data of the second period stored in the non-volatile memory of the other party to other devices via a communication terminal mounted on the vehicle at a sending timing after the backoff timing. On the other hand, if the data volume exceeds the sending upper limit threshold, the sending processing unit sends a collection request signal to the other devices via the communication terminal to request the collection of the driving data of the second period.

[0008] In one embodiment, the driving data recording device further includes: a switching processing unit that exchanges the non-volatile memory of one side with the non-volatile memory of the other side whenever a switching period longer than the second period has passed, or whenever the number of times the driving data of the first period is saved in the non-volatile memory of one side reaches a specified number of switching times.

[0009] In one embodiment, the driving data recording device further includes a detection unit configured to detect occurrence of a predetermined event and identify the type of the event that has occurred, and the second copy processing unit determines the length of the second period based on the identified type of the event.

[0010] In one embodiment, the driving data recording device further includes a detection unit configured to detect the occurrence of a predetermined event and identify the type of the event. Furthermore, the second copy processing unit determines, based on the identified type of event, the type of data items to be included in the driving data to be copied from one non-volatile memory and stored in the other non-volatile memory.

[0011] According to another embodiment, a driving data recording method is provided. The driving data recording method includes: storing driving data representing a condition of a vehicle during driving or a condition surrounding the vehicle in a volatile memory; each time a first period elapses, copying the driving data for the first period stored in the volatile memory and storing it in one of a first non-volatile memory and a second non-volatile memory; and, when a retreat timing is reached after a predetermined time has elapsed since a timing at which a predetermined event is detected, copying the driving data for a second period from the first non-volatile memory and storing it in the other of the first non-volatile memory and the second non-volatile memory, wherein the second period includes the timing at which the event is detected and is longer than the first period.

[0012] According to another embodiment, a computer program product for recording driving data is provided. The computer program product includes instructions for causing a processor mounted on a vehicle to execute the following processing: storing driving data representing a condition of the vehicle during driving or a condition surrounding the vehicle in a volatile memory; copying the driving data for the first period stored in the volatile memory and storing it in one of a first non-volatile memory and a second non-volatile memory each time a first period elapses; and, when a retreat timing is reached after a predetermined time has elapsed since a timing at which a predetermined event is detected, copying the driving data for a second period from the first non-volatile memory and storing it in the other of the first and second non-volatile memories, wherein the second period includes the timing at which the event is detected and is longer than the first period.

[0013] The driving data recording device of the present disclosure has the effect of being able to record driving data of a vehicle over a relatively long period of time, wherein the relatively long period includes the timing at which an event occurs while the vehicle is traveling. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the structure of a vehicle equipped with a driving data recording device.

[0015] Figure 2 This is a diagram of the hardware configuration of the driving data recording device.

[0016] Figure 3 This is a functional block diagram of a processor of a driving data recording device.

[0017] Figure 4 This is a diagram schematically illustrating the driving data recording process.

[0018] Figure 5 This is a flowchart of the driving data recording process. DETAILED DESCRIPTION

[0019] The following describes a driving data recording device, a driving data recording method executed in the driving data recording device, and a computer program for driving data recording, with reference to the accompanying drawings. The driving data recording device is mounted on a vehicle and sequentially stores driving data representing the vehicle's condition during driving or the condition of the vehicle's surroundings in a volatile memory. Furthermore, each time a first period elapses, the driving data recording device stores a copy of the driving data stored in the volatile memory for the first period in one of two non-volatile memories (hereinafter, storing a copy of the driving data stored in one memory in the other memory is simply referred to as copying and storing the driving data or copying and storing the driving data). Furthermore, at a retreat timing, which occurs after a predetermined time has passed since the timing at which the occurrence of a predetermined event is detected, the driving data recording device copies the driving data for a second period from one non-volatile memory to the other non-volatile memory, where the second period includes the timing at which the occurrence of the event is detected and is longer than the first period. Thus, the travel data recording device records travel data for a relatively long period including the timing at which an event occurs while the vehicle is traveling.

[0020] Figure 1 This is a schematic diagram of a vehicle equipped with a driving data recording device. Vehicle 1 has at least one behavior sensor 2, a camera 3, a wireless communication terminal 4, a driving data recording device 5, and an electronic control unit (ECU: Electronic Control Unit) 6 that controls various parts of vehicle 1. The behavior sensor 2, camera 3, wireless communication terminal 4, and ECU 6 are connected to the driving data recording device 5 in a communicative manner. In addition, a distance measuring sensor (not shown) such as LiDAR (Light Detection and Ranging) or radar that measures the distance to objects around vehicle 1 can also be provided in vehicle 1. In addition, a device (not shown) for measuring the position of vehicle 1 through a satellite positioning system such as a GPS (Global Positioning System: Global Positioning System) receiver can also be provided in vehicle 1.

[0021] At least one behavior sensor 2 measures the behavior of the vehicle 1. Behavior sensors 2 may include, for example, at least one of a velocity sensor, an acceleration sensor, and an angular velocity sensor. Each behavior sensor 2 generates a sensor signal representing the behavior of the vehicle 1 and outputs the sensor signal to the ECU 6. Furthermore, each behavior sensor 2 may also output the generated sensor signal to the driving data recording device 5.

[0022] The camera 3 captures a predetermined area around the vehicle 1 or a predetermined area inside the vehicle 1, generates an image representing the predetermined area at predetermined intervals, and outputs the generated image to the driving data recording device 5 and the ECU 6. It should be noted that the predetermined area is, for example, an area in front of or behind the vehicle 1, or an area inside the vehicle 1 that includes the position of the driver of the vehicle 1. It should be noted that a plurality of cameras 3 with different shooting directions or focal lengths may also be provided in the vehicle 1. Hereinafter, the image representing the predetermined area around the vehicle 1 will be referred to as an outside-vehicle image. In addition, the image representing the driver will be referred to as a driver image.

[0023] The wireless communication terminal 4 is an example of a communication device, performing wireless communication processing in accordance with a prescribed wireless communication standard. For example, it accesses a wireless base station (not shown) and connects to a server (not shown) that collects driving data via the wireless base station and a communication network. Specifically, a communication line is established between the wireless communication terminal 4 and the server via the wireless base station and the communication network. Furthermore, the wireless communication terminal 4 generates an uplink wireless signal containing the driving data to be collected, received from the driving data recording device 5, and transmits this uplink wireless signal to the wireless base station, thereby transmitting the driving data to the server.

[0024] ECU 6 controls various components of vehicle 1. Specifically, ECU 6 uses sensor signals from behavior sensor 2 to assist the driver of vehicle 1. Alternatively, ECU 6 can use sensor signals from behavior sensor 2 to perform autonomous driving control of vehicle 1. Furthermore, ECU 6 outputs a status signal indicating the status of vehicle 1 to driving data recorder 5. If an abnormality is detected in any of the components of vehicle 1 being controlled, or in ECU 6 itself, ECU 6 includes information indicating the detected abnormality in the status signal.

[0025] Figure 2 This is a diagram showing the hardware configuration of the driving data recording device 5. The driving data recording device 5 includes a communication interface 11, a volatile memory 12, a first non-volatile memory 13, a second non-volatile memory 14, and a processor 15. Furthermore, the driving data recording device 5 may be provided with an external interface (not shown) for connecting peripheral devices that conforms to a prescribed interface standard, such as USB (Universal Serial Bus) (registered trademark).

[0026] The communication interface 11 is an example of an in-vehicle communication unit, and has an interface circuit for connecting the driving data recording device 5 to each behavior sensor 2, the camera 3, the wireless communication terminal 4, and the ECU 6 in a communicative manner. Furthermore, whenever the communication interface 11 receives a sensor signal from each behavior sensor 2, the communication interface 11 transmits the received sensor signal to the processor 15. It should be noted that the communication interface 11 can also receive sensor signals from each behavior sensor 2 via the ECU 6. In addition, whenever the communication interface 11 receives an image from the camera 3, the communication interface 11 transmits the received image to the processor 15. Furthermore, whenever the communication interface 11 receives information from a server from the wireless communication terminal 4, the communication interface 11 transmits the information to the processor 15. In addition, when the communication interface 11 receives a status signal indicating the status of the vehicle 1 from the ECU 6, the communication interface 11 transmits the status signal to the processor 15. Furthermore, the communication interface 11 outputs the driving data received from the processor 15 to the wireless communication terminal 4.

[0027] The volatile memory 12 is configured as an integrated circuit of a volatile semiconductor memory, such as DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory). In this embodiment, the volatile memory 12 is configured as a ring buffer, into which driving data is sequentially written by the processor 15. It should be noted that the volatile memory 12 has a storage area of a size sufficient to store the amount of data equivalent to driving data acquired during a period having a first length (hereinafter referred to as simply the first period) multiplied by a predetermined margin factor (1 or greater, for example, 1.1 to 1.3). The first period is the period during which driving data stored in the volatile memory 12 is copied to either the first non-volatile memory 13 or the second non-volatile memory 14. The first period is set to, for example, a length of several to ten minutes. Furthermore, when the storage area of the volatile memory 12 becomes full, driving data is overwritten in order, starting with the oldest data.

[0028] The first nonvolatile memory 13 and the second nonvolatile memory 14 are each configured as a nonvolatile semiconductor memory integrated circuit. The first nonvolatile memory 13 and the second nonvolatile memory 14 may be configured as separate integrated circuits or as different storage areas in one integrated circuit.

[0029] Driving data stored in volatile memory 12 is copied and stored in one of the first and second nonvolatile memories 13, 14, on a first-period basis. Furthermore, after a predetermined event is detected, driving data stored in one of the first and second nonvolatile memories 13, 14 for a second period (hereinafter referred to simply as the second period) is copied and stored in the other of the first and second nonvolatile memories 13, 14. Therefore, each of first and second nonvolatile memories 13, 14 has a storage area sized to store the amount of data obtained by multiplying the amount of driving data obtained in the second period by a predetermined margin factor (1 or greater, for example, 1.1 to 1.3).

[0030] The processor 15 includes one or more CPUs (Central Processing Units) and their peripheral circuits. The processor 15 may also include other arithmetic circuits such as a logic operation unit, a numerical operation unit, or a graphics processing unit. Furthermore, while the vehicle 1 is traveling, the processor 15 executes driving data recording processing.

[0031] Figure 3 This is a functional block diagram of the processor 15 related to driving data recording processing. The processor 15 includes a storage processing unit 21, a first copy processing unit 22, a detection unit 23, a second copy processing unit 24, a transmission processing unit 25, and a switching processing unit 26. These components of the processor 15 are, for example, functional modules implemented by a computer program running on the processor 15. Alternatively, these components of the processor 15 may be dedicated arithmetic circuits provided in the processor 15.

[0032] The storage processing unit 21 sequentially stores driving data in the volatile memory 12. As described above, driving data is data indicating the condition of the vehicle 1 or the surrounding conditions of the vehicle 1 while it is traveling. Driving data may include, for example, at least one of a value indicating the behavior of the vehicle 1 as indicated by a sensor signal from the behavior sensor 2, an image of the vehicle exterior or the driver obtained by the camera 3, a value related to the driving operation or control of the vehicle 1 obtained from the ECU 6, and data indicating the operating state of the ECU 6. It should be noted that the value indicating the behavior of the vehicle 1 may include, for example, at least one of the vehicle's speed, acceleration, and angular velocity. Furthermore, the value related to the driving operation or control of the vehicle 1 may include, for example, at least one of the steering angle of the steering wheel, the accelerator position, the amount of brake pedal depression, the remaining battery charge, the headlight lighting pattern, and the wiper operation pattern. Furthermore, if the vehicle 1 is equipped with a distance measuring sensor, the distance to objects surrounding the vehicle 1, indicated by the distance measuring signal generated by the distance measuring sensor, may also be included in the driving data. Furthermore, when the vehicle 1 is provided with a positioning device such as a GPS receiver, the position of the vehicle 1 measured by the device may also be included in the travel data.

[0033] Each time a set of data to be included in driving data is received from the behavior sensor 2, camera 3, and ECU 6, the storage processing unit 21 generates driving data by including the set of data in a single driving data item. In this case, the storage processing unit 21 generates a single driving data item by including the set of data in the driving data item according to a predetermined format. Alternatively, the storage processing unit 21 may compress the set of data item using a predetermined compression format and then include the set of data item in the driving data item. A single driving data item includes a set of data item for which the difference in reception timing at the driving data recording device 5 is within a predetermined tolerance (e.g., 100 milliseconds to 1 second). The storage processing unit 21 may also include time information indicating the time when the driving data item was generated in the driving data item. Each time the storage processing unit 21 generates driving data, it stores the generated driving data item in a free area of the volatile memory 12. However, if the free area in the volatile memory 12 is insufficient to store the driving data item, the storage processing unit 21 overwrites the oldest driving data item stored in the volatile memory 12 with the latest driving data item.

[0034] Each time a first period elapses, the first copy processing unit 22 copies the most recent first period's worth of driving data stored in the volatile memory 12 and stores it in one of the first non-volatile memory 13 and the second non-volatile memory 14. It should be noted that the first copy processing unit 22 may erase the driving data stored in the volatile memory 12 as the copy source, or may retain the driving data intact. Hereinafter, the non-volatile memory of the first or second non-volatile memory 13, 14 that copies and stores driving data from the volatile memory 12 will sometimes be referred to as the primary copy memory. It should be noted that a flag indicating the primary copy memory and the other non-volatile memory is stored in a storage area outside the driving data storage area of either the first or second non-volatile memory 13, 14. The first copy processing unit 22 can determine which of the first or second non-volatile memory 13, 14 is the primary copy memory by referring to this flag.

[0035] After the ignition switch of vehicle 1 is turned on, driving data is sequentially written to the primary copy memory in units of the first period. Therefore, all driving data after the ignition switch is turned on is stored until the storage area of the primary copy memory is full. It should be noted that when the storage area of the primary copy memory is full, the first copy processing unit 22 overwrites the oldest driving data stored in the primary copy memory with the latest driving data for the first period.

[0036] Whenever the copying and saving of the driving data of the first period to the primary copy memory is completed, the first copy processing unit 22 notifies the switching processing unit 26 that the copying and saving of the driving data of the first period to the primary copy memory has been completed.

[0037] The detection unit 23 detects the occurrence of a predetermined event in or around the vehicle 1. The predetermined event is an event for which collection of driving data before and after the occurrence of the event is requested, and may be, for example, an accident, the vehicle 1's emergency avoidance of a certain danger, or an abnormality of the driver of the vehicle 1.

[0038] Therefore, the detection unit 23 determines whether the value representing the behavior of the vehicle 1 indicated by the sensor signal from the behavior sensor 2, the value related to the driving operation or control of the vehicle 1 from the ECU 6, or the data indicating the operating state of the ECU 6 satisfies the prescribed event detection conditions. If the prescribed event detection conditions are met, the detection unit 23 determines that the prescribed event has occurred and detects the occurrence of the event. On the other hand, if the prescribed event detection conditions are not met, the detection unit 23 does not detect the occurrence of the prescribed event.

[0039] For example, the event detection condition may be that the absolute value of the acceleration of vehicle 1 or the absolute value of the angular velocity of vehicle 1, as indicated by the sensor signal from behavior sensor 2, exceeds a predetermined threshold. Alternatively, the event detection condition may be that the change in the steering angle received from ECU 6 within a predetermined sampling interval (e.g., 100 milliseconds to 1 second) exceeds a predetermined threshold. Alternatively, the event detection condition may be that the data indicating the operating status of ECU 6 includes a value indicating a certain fault.

[0040] Alternatively, the detection unit 23 may determine whether the event detection conditions are met based on the image outside the vehicle or the image of the driver from the camera 3. In this case, the detection unit 23 inputs the image outside the vehicle or the image of the driver into a classifier that has been pre-trained to determine whether a predetermined event has occurred. If the classifier outputs a classification result indicating that the predetermined event has occurred, the detection unit 23 determines that the event detection conditions are met. It should be noted that the classifier may be constructed as a deep neural network (DNN) in the form of a convolutional neural network (CNN), wherein the DNN has one or more convolutional layers and one or more fully-connected layers, sequentially from the input side. Alternatively, the classifier may be constructed using a machine learning method other than neural networks, such as a support vector machine or an adaptive boosting (AdaBoost) classifier. Such a classifier is pre-trained using a number of training images, including images representing situations corresponding to predetermined events, such as accidents or abnormal situations, using a prescribed supervised learning method such as backpropagation of errors.

[0041] When the detection unit 23 detects the occurrence of a predetermined event, the detection unit 23 notifies the second copy processing unit 24 of the detection of the occurrence of the predetermined event.

[0042] When the retreat timing arrives after a predetermined time (e.g., several tens of seconds to several minutes) has elapsed since the occurrence of the predetermined event was detected, the second copy processing unit 24 copies the driving data corresponding to the second period of time from the driving data stored in the primary copy memory from the primary copy memory and stores the data in the other of the first non-volatile memory 13 and the second non-volatile memory 14. Hereinafter, the other of the first non-volatile memory 13 and the second non-volatile memory 14 may be referred to as the secondary copy memory.

[0043] It should be noted that the second period is a period that includes the timing at which the occurrence of the event is detected and is longer than the first period. For example, it can be set to a period of several tens of minutes to more than an hour. Therefore, when the timing at which the ignition switch is turned on is earlier than the timing that is earlier than the upper limit value of the length of the second period (hereinafter referred to as the upper limit length start timing) from the backoff timing, the second copy processing unit 24 can set the upper limit length start timing as the start timing of the second period. On the other hand, when the upper limit length start timing is earlier than the timing at which the ignition switch is turned on, the second copy processing unit 24 can set the timing at which the ignition switch is turned on as the start timing of the second period. It should be noted that in the above example, the backoff timing is set to the end point of the second period, but the end point of the second period can also be before the backoff timing as long as it is after the timing at which the occurrence of the event is detected.

[0044] When the copying and storage of the second period's driving data in the secondary copy memory is complete, the second copy processing unit 24 notifies the transmission processing unit 25 of the completion of the copying and storage of the second period's driving data in the secondary copy memory. Furthermore, when the copying and storage in the secondary copy memory is complete, the second copy processing unit 24 may erase the copy source driving data stored in the primary copy memory or retain the driving data intact. Furthermore, the second copy processing unit 24 may erase the driving data stored in the primary copy memory when the ignition switch of the vehicle 1 is turned off without detecting a predetermined event.

[0045] When the transmission processing unit 25 is notified that the copying and storage of the driving data for the second period in the secondary copy memory has been completed, the transmission processing unit 25 transmits the driving data for the second period stored in the secondary copy memory to the server via the communication interface 11 and the wireless communication terminal 4 at a subsequent predetermined transmission timing. The server is an example of another device.

[0046] The predetermined transmission timing may be, for example, immediately after notification of completion of copying and storing the driving data for the second period in the secondary copy memory, or may be any timing from immediately after the notification until the ignition switch of the vehicle 1 is turned off. Alternatively, the predetermined transmission timing may be the timing when the ignition switch is next turned on after being temporarily turned off.

[0047] According to a variation, the transmission processing unit 25 may also determine whether the amount of driving data for the second period stored in the secondary copy memory is less than or equal to a specified upper limit threshold for transmission. The upper limit threshold is set to a value equivalent to the amount of data that can be communicated via the wireless communication terminal 4 within a specified time period (e.g., several minutes). If the amount of data is less than or equal to the upper limit threshold, the transmission processing unit 25 transmits the driving data for the second period stored in the secondary copy memory to the server via the communication interface 11 and the wireless communication terminal 4 at the transmission timing. On the other hand, if the amount of driving data for the second period exceeds the upper limit threshold for transmission, the transmission processing unit 25 transmits a collection request signal to the server via the communication interface 11 and the wireless communication terminal 4 at the transmission timing, requesting the collection of driving data for the second period. It should be noted that the transmission processing unit 25 includes vehicle 1 identification information and information indicating the amount of driving data for the second period in the collection request signal. In this case, the driving data stored in the secondary copy memory can be output to a peripheral device (not shown) connected via an external interface. Furthermore, the transmission processing unit 25 may cause a display device (not shown) included in the driving data recording device 5 or a display device (not shown) provided in the vehicle cabin of the vehicle 1 to display a message instructing the driver to go to a facility that can handle data collection.

[0048] According to this modification, the transmission processing unit 25 can appropriately determine whether to transmit the driving data by wireless communication or to collect the driving data individually, according to the amount of driving data stored in the secondary copy memory.

[0049] After the driving data is transmitted via the wireless communication terminal 4 or after the driving data is output to the peripheral device, the transmission processing unit 25 erases the driving data from the secondary copy memory. Furthermore, if the driving data stored in the secondary copy memory has not been collected even after a certain period of time (e.g., several days to several weeks) has passed since the collection request signal was sent to the server, the transmission processing unit 25 may erase the driving data from the secondary copy memory.

[0050] It should be noted that, if the amount of driving data for the second period exceeds the upper transmission threshold, the transmission processing unit 25 may transmit a third period of driving data, shorter than the second period, along with a collection request signal, to the server via the communication interface 11 and the wireless communication terminal 4. In this case, the third period may be set to be a period of several tens of seconds to several minutes, including the timing of the event occurrence. Furthermore, if the server determines that all driving data for the second period is necessary, the driving data for the second period may be collected via the external interface. On the other hand, if the server determines that all driving data for the second period is not necessary, the server may transmit a discard instruction to the vehicle 1. Furthermore, upon receiving the discard instruction via the wireless communication terminal 4 and the communication interface 11, the transmission processing unit 25 may erase all driving data stored in the secondary copy memory.

[0051] Each time a predetermined switching period elapses, or each time the number of times the driving data from the first period has been copied and stored in the primary copy memory reaches a predetermined switching count, the switching processing unit 26 swaps the primary copy memory with the secondary copy memory. The predetermined switching period can be longer than the second period, for example, several to several dozen times the length of the second period. Each time the switching processing unit 26 swaps the primary copy memory with the secondary copy memory, it stores the date and time of the swap in a storage area other than the driving data storage area in the first non-volatile memory 13 or the second non-volatile memory 14. Furthermore, the switching processing unit 26 compares the time elapsed since the last swap with the switching period. If the elapsed time reaches the switching period, the primary copy memory and the secondary copy memory are swapped. Alternatively, each time the switching processing unit 26 receives notification from the first copy processing unit 22 that the driving data for the first period has been copied and stored, it increments the number of copies and stores by one and compares this number of copies and stores with the predetermined switching count. If the number of copies and saves reaches a predetermined switching count, the switching unit 26 simply swaps the primary and secondary copy memories. It should be noted that the predetermined switching count can be several to several dozen times the number of copies in the first period included in the second period. If the switching unit 26 determines that the primary and secondary copy memories should be swapped, it executes the swap when the ignition switch of the vehicle 1 is subsequently turned off. However, if driving data is stored in the secondary copy memory, the switching unit 26 can swap the primary and secondary copy memories after the driving data is erased from the secondary copy memory. When the primary and secondary copy memories are swapped, the switching unit 26 rewrites the flags indicating the primary and secondary copy memories in the storage areas other than the driving data storage area in the first non-volatile memory 13 or the second non-volatile memory 14 to the swapped values.

[0052] By swapping the primary copy memory and the secondary copy memory at regular intervals, the usage of the two nonvolatile memories is evened out. Therefore, the driving data recording device 5 can suppress the occurrence of failures in the two nonvolatile memories.

[0053] Figure 4 This is a diagram explaining the outline of the driving data recording process. Figure 4 , the vertical axis represents the elapsed time.

[0054] After the ignition switch of vehicle 1 is turned on, driving data is sequentially stored in volatile memory 12. Furthermore, as shown in operating state S1, at the time point after the first period T has elapsed, the driving data corresponding to the first period T stored in volatile memory 12 is copied and stored in the primary copy memory. This copying and storage of driving data to the primary copy memory is repeated each time the first period T has elapsed. This copying and storage is performed regardless of whether a predetermined event has occurred. Therefore, as shown in operating state S2, even after the occurrence of a predetermined event has been detected, driving data is copied and stored from volatile memory 12 to the primary copy memory.

[0055] When the retreat timing arrives after the occurrence of a predetermined event, as shown in operating state S3, the driving data for the second period ending at the retreat timing is copied from the primary copy memory and stored in the secondary copy memory. As described above, the end point of the second period may be before the retreat timing, as long as it is after the occurrence timing of the event.

[0056] Then, as shown in operation state S4, when the ignition switch of vehicle 1 is turned off, the driving data of the second period stored in the secondary copy memory is transmitted to the server. In addition, the driving data in the primary copy memory and the secondary copy memory are erased.

[0057] Figure 5 The processor 15 executes the driving data recording process according to the following operational flowchart.

[0058] The storage processing unit 21 sequentially stores the driving data in the volatile memory 12 (step S101). Furthermore, each time the first period elapses, the first copy processing unit 22 copies the driving data corresponding to the latest first period stored in the volatile memory 12 and stores it in the primary copy memory in the first non-volatile memory 13 and the second non-volatile memory 14 (step S102).

[0059] The detection unit 23 determines whether or not the occurrence of a predetermined event is detected in the vehicle 1 or around the vehicle 1 (step S103 ).

[0060] If the occurrence of the predetermined event is not detected (step S103 - No), the processor 15 repeats the processing from step S101 onward. On the other hand, if the occurrence of the predetermined event is detected (step S103 - Yes), when the retreat timing arrives, the second copy processing unit 24 copies the driving data for the second period stored in the primary copy memory and stores it in the secondary copy memory in the first non-volatile memory 13 and the second non-volatile memory 14 (step S104).

[0061] The transmission processing unit 25 determines whether the amount of driving data for the second period stored in the secondary copy memory is less than or equal to a predetermined upper limit threshold ThU for transmission (step S105). If the amount of data is less than or equal to the upper limit threshold ThU (step S105 - Yes), the transmission processing unit 25 transmits the driving data for the second period stored in the secondary copy memory to the server via the communication interface 11 and the wireless communication terminal 4 (step S106). On the other hand, if the amount of data exceeds the upper limit threshold ThU (step S105 - No), the transmission processing unit 25 transmits a collection request signal to the server via the communication interface 11 and the wireless communication terminal 4 (step S107).

[0062] After step S106 or step S107, the switching processing unit 26 determines whether the time elapsed since the last swap between the primary and secondary copy memories has reached the swap period (step S108). If the time elapsed has reached the swap period (step S108 - Yes), the switching processing unit 26 swaps the primary and secondary copy memories (step S109). After step S109, or if the time elapsed has not reached the swap period (step S108 - No), the processor 15 terminates the driving data recording process.

[0063] It should be noted that, in step S108, as described above, the switching processing unit 26 may determine whether the number of times the driving data corresponding to the first period has been copied and stored in the primary copy memory has reached the switching number. Furthermore, the switching processing unit 26 may execute the process of step S109 if the number of times the driving data has been copied and stored has reached the switching number.

[0064] As described above, each time a first period elapses, the driving data recording device copies the driving data for the first period stored in the volatile memory and stores it in one of the two non-volatile memories. Furthermore, at the retreat timing, which occurs after a predetermined time has passed since the detection of a predetermined event, the driving data recording device copies the driving data for a second period from one of the non-volatile memories and stores it in the other non-volatile memory. This second period includes the timing of the event detection and is longer than the first period. Therefore, the driving data recording device can record driving data for a longer period, including the timing of the event occurring while the vehicle is traveling.

[0065] According to a modified example, the length of the second period can also be changed according to the type of event that occurs. In this case, the event detection condition is pre-set according to each type of event. For example, in the case where the type of event is the occurrence of an accident, the event detection condition can be set to the absolute value of the acceleration or the absolute value of the angular velocity being greater than or equal to a specified threshold value. On the other hand, if the type of event is that an abnormality has occurred in the driver, the event detection condition can be set to detecting the abnormality of the driver from the driver image. In addition, the detection unit 23 determines whether the event occurrence condition corresponding to the type is met according to each type of event. When a certain event occurrence condition is met, the detection unit 23 determines the type of the event that has occurred as the type corresponding to the event occurrence condition that is met. In addition, the detection unit 23 not only notifies the second copy processing unit 24 of the detected occurrence of the event, but also notifies the second copy processing unit 24 of the determined type of event.

[0066] The second copy processing unit 24 determines the upper limit of the second period length corresponding to the type of event determined by the detection unit 23 by referring to a table that shows the relationship between the type of event and the upper limit of the second period length. For example, if the type of event that occurred is a driver abnormality, the second period is set to be longer than the second period if the type of event that occurred is an accident. Such a table can be pre-stored in a storage area outside the driving data storage area of the first non-volatile memory 13 or the second non-volatile memory 14. Then, the second copy processing unit 24 performs the same processing as the above embodiment according to the determined upper limit of the second period, thereby copying the driving data for the second period from the primary copy memory to the secondary copy memory for storage. According to this modified example, the driving data recording device 5 can record driving data of an appropriate length corresponding to the type of event that occurred while the vehicle 1 was driving.

[0067] Furthermore, in the above-described embodiment or variations, the types of data items included in the driving data to be transmitted to the server or collected via the external interface, that is, the types of data items included in the driving data to be copied and stored in the secondary copy memory, can also be determined based on the type of event that occurred. For example, if the type of event that occurred is an accident, values representing the behavior of vehicle 1, such as acceleration or angular velocity, values related to the driving operation or control of vehicle 1, and images outside the vehicle are determined as data items. Furthermore, if the type of event that occurred is a driver abnormality, values related to the driving operation or control of vehicle 1 and images of the driver are determined as data items. In this case, the second copy processing unit 24 determines the types of data items to be included in the driving data by referring to the type of event detected and determined by the detection unit 23 and a table indicating the relationship between event types and data item types. Such a table can be pre-stored in a storage area of the first non-volatile memory 13 or the second non-volatile memory 14, other than the driving data storage area. Then, the second copy processing unit 24 copies the data items of the specified type for the second period from the driving data stored in the primary copy memory and stores them in the secondary copy memory. According to this variation, the driving data recording device 5 can record driving data containing data items of appropriate types corresponding to the types of events that occurred while the vehicle 1 was driving.

[0068] Driving data transmitted from a driving data recording device according to the above-described embodiment or variations to a server or collected via an external interface is used to analyze the cause of an incident, improve a vehicle's driving assistance algorithm, or improve an autonomous driving control algorithm. Furthermore, the improved driving assistance algorithm or autonomous driving control algorithm can be distributed from the server to various vehicles utilizing these algorithms.

[0069] The computer program that implements the functions of the processor 15 of the driving data recording device 5 based on the above-mentioned embodiments or modifications can also be provided as a computer program product, for example, in the form of a computer-readable portable recording medium such as a semiconductor memory, a magnetic recording medium or an optical recording medium.

[0070] As described above, those skilled in the art can make various modifications within the scope of the present invention in accordance with the embodiments.

Claims

1. A driving data recording device comprising: Volatile memory; a first non-volatile memory; a second non-volatile memory; a storage processing unit that stores driving data indicating a condition of the vehicle during driving or a condition of the surroundings of the vehicle in the volatile memory; a first copy processing unit that copies the driving data for the first period stored in the volatile memory and stores the copy in one of the first nonvolatile memory and the second nonvolatile memory whenever a first period elapses; as well as A second copy processing unit copies the driving data of a second period in the driving data stored in the non-volatile memory of the one party from the non-volatile memory of the one party and stores it in the non-volatile memory of the other party between the first non-volatile memory and the second non-volatile memory when a retreat timing comes after a predetermined time has passed since the timing of detecting the occurrence of a predetermined event, wherein the second period includes the timing of detecting the occurrence of the event and is longer than the first period.

2. The driving data recording device according to claim 1, further comprising: The sending processing unit determines whether the data volume of the driving data of the second period is less than or equal to a specified sending upper limit threshold. If the data volume is less than or equal to the sending upper limit threshold, the sending processing unit sends the driving data of the second period stored in the non-volatile memory of the other party to the other device via the communication terminal mounted on the vehicle at the sending timing after the backoff timing. On the other hand, if the data volume exceeds the sending upper limit threshold, the sending processing unit sends a collection request signal to the other device via the communication terminal to request the collection of the driving data of the second period.

3. The driving data recording device according to claim 1 or 2, further comprising: The switching processing unit exchanges the nonvolatile memory of one side with the nonvolatile memory of the other side each time a switching period longer than the second period has passed or each time the number of times the driving data of the first period has been saved in the nonvolatile memory of the one side reaches a predetermined switching number.

4. The driving data recording device according to claim 1 or 2, further comprising: a detection unit that detects the occurrence of the predetermined event and determines the type of the event that occurs, The second copy processing unit determines the length of the second period according to the type of the identified event.

5. The driving data recording device according to claim 1 or 2, further comprising: a detection unit that detects the occurrence of the predetermined event and determines the type of the event that occurs, The second copy processing unit determines, based on the specified event type, the type of data item included in the travel data to be copied from the one nonvolatile memory and stored in the other nonvolatile memory.

6. A driving data recording method, comprising: storing driving data indicating a condition of the vehicle or a condition surrounding the vehicle during driving in a volatile memory; Whenever a first period elapses, the driving data for the first period stored in the volatile memory is copied and stored in one of a first nonvolatile memory and a second nonvolatile memory; as well as When a retreat timing comes after a specified time has passed since the timing at which the occurrence of a specified event is detected, driving data of a second period in the driving data stored in the non-volatile memory of the one party is copied from the non-volatile memory of the one party and stored in the non-volatile memory of the other party, the first non-volatile memory and the second non-volatile memory, wherein the second period includes the timing at which the occurrence of the event is detected and is longer than the first period.

7. A computer program product for recording driving data, comprising instructions for causing a processor mounted on a vehicle to execute the following processing: storing driving data indicating a condition of the vehicle or a condition surrounding the vehicle during driving of the vehicle in a volatile memory; Whenever a first period elapses, the driving data for the first period stored in the volatile memory is copied and stored in one of a first nonvolatile memory and a second nonvolatile memory; as well as When a retreat timing comes after a specified time has passed since the timing at which the occurrence of a specified event is detected, driving data of a second period in the driving data stored in the non-volatile memory of the one party is copied from the non-volatile memory of the one party and stored in the non-volatile memory of the other party, the first non-volatile memory and the second non-volatile memory, wherein the second period includes the timing at which the occurrence of the event is detected and is longer than the first period.

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